This application claims the benefit of Japanese Application Number 2002-197678 filed Jul. 5, 2002, the entity of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a door station apparatus with an electric lock. More particularly, it relates to a door station apparatus with an electric lock, having a room master station which is installed in a room, an entrance door station which serves to call and talk to an inhabitant, an electric lock which is mounted on the door or gate of an entrance, and a power source unit which feeds a supply voltage to the room master station.
2. Description of the Related Art
As a prior-art door station apparatus with an electric lock, one having a construction shown in FIG. 6 has been known. The door station apparatus with the electric lock as shown in the block diagram of FIG. 6 is constructed of a plurality of room master stations 51 (in FIG. 6, four stations) which are installed in corresponding rooms so as to talk with a visitor and each of which is furnished with an electric lock button 58 for controlling the electric lock 53, a single entrance door station 52 which is connected to the individual room master stations 51 so as to call and talk with inhabitants, and a power source unit 54 which feeds supply voltages to the room master stations 51 and the electric lock 53 mounted on the door or gate of an entrance. Besides, the individual room master stations 51, and the entrance door station 52 are respectively connected to the power source unit 54 by transmission lines of two-wire system 55, while the individual room master stations 51, and the entrance door station 52 are connected by transmission lines of two-wire system 56 for the talking/calling. Further, the electric lock 53 is connected to the power source unit 54 by a transmission line of two-wire system 57, but one wire of the transmission line 57 is led to the individual room master stations 51.
Here in the door station apparatus with the electric lock, when the visitor calls over the entrance door station 52, buzz is emitted at the called room master station 51 so as to notify the arrival of the visitor to the inhabitant. Subsequently, when the inhabitant answers by taking up a handset, he/she is permitted to talk with the entrance door station 52. Further, when the inhabitant depresses the electric lock button 58 of the room master station 51, the supply voltage is fed from the power source unit 54 to the electric lock 53, and the electric lock 53 is released. In the prior-art door station apparatus with the electric lock, however, the devices are connected to the power source unit 54, and the electric lock 53 is connected to the respective room master stations 51. Therefore, the number of necessary wiring lines is large, and arrangements of the lines are troublesome. Accordingly, the installation of the door station device is troublesome. Especially in case of installing the door station apparatus with an existing house, the installation is difficult due to an insufficient number of wiring lines.